GRE key

Junos OS supports configuring a key to identify traffic flows in a GRE tunnel as defined in RFC2890. You must configure the key on the routers on both endpoints of a tunnel and create an export policy to populate the key in the forwarding table. You can configure dynamic-tunnel-gre-key at the [edit routing-options dynamic-tunnels tunnel-attributes name] hierarchy level.

Starting in 26.2, you can configure a GRE tunnel key to differentiate multiple tunnels that share identical source and destination IP endpoints. The device inserts the key in outbound GRE packets and validates or parses keys from incoming GRE packets.